Argument 410: on Exchanges and the Different Value of Money in Different Places, Not in Comparison to Small Coins Any Longer But Because of Concurrent Circumstances. Thus, We End Our Study on Money (Treatise on Money) (Excerpt‪)‬

In Argument 406 we introduced a distinction in the value of money, considering it according to a double aspect. In the second of these, money, not this or that from a certain region, but all of money is worth more in one place than in another comparing equal amounts in one and the other, even if in one and the other place they are equal coins as far as material, weight, metal alloy, and the seal itself, and to which the law has assigned the same value in comparison to the other coins in the place. We were saying that this value does not originate in the currency itself, but in the circumstances, and is a very inconstant value, which is not fixed in an indivisible point but moves within certain limits. It is like the value of the other merchandise, which as long as it is not appraised by the law is not fixed in one exact point. What we are trying to find out now is if for reason of the difference in this type of value it is licit to increase the price of exchanges from one place to another or if it is more convenient to reduce it sometimes according to the greater or lesser value that money has in that place. Soto, Navarro, and others respond affirmatively, (1) and their opinion may be proven because the commutation of two things which are equal in value is in itself licit. Therefore, if at one point 360 maravedis in Flanders are worth the same as 400 in Medina (for the scarcity of coin in Flanders and the abundance in Medina, and for other concurrent reasons), it shall be licit--if all other circumstances are equal--to exchange 360 maravedis given in Flanders for 400 to be delivered in Medina. And, quite the contrary, it shall be licit to exchange 400 given in Medina for 360 to be delivered in Flanders, the same as it is licit to exchange one hundred units of wine or oil given in the Spanish territories for eighty that are given in Flanders. And on the contrary, eighty that are given in Flanders shall be exchanged for one hundred to be given in the Spanish territories, as eighty units of wine or oil are worth in Flanders the same as one hundred in the Spanish territories, reason for which wine and oil are taken to Flanders.